Orthokeratology or ortho-k is a method of molding or shaping the cornea with contact lenses to improve vision without using eye glasses or lenses. It is the process which involves the programmed application of contact shaping lenses to systematically and predictably reshape the surface of the cornea to reduce the need for correction of myopia temporarily.
Orthokeratology may be undertaken by wearing either daily or overnight wear lenses. Discussed below are the features of each type of lens that will help you decide which method of orthokeratology will work best for you.
Daily Wear
Here are the features of a daily wear orthokeratology shaping lens:
• This lens which includes PMMA lens and gas permeable plastics of medium and low permeabilities was more popular in the past. Due to its poor physiologic effects, it can only be worn during daytime. The materials used in making this lens are not safe for overnight wear unlike the current ortho-k lens which is larger and thicker.
• This lens usually employed conventional rigid contact lens designs. It progressively fits as flat as possible to reduce the height of the central cornea and reduce myopia. In some instances, however, the vision became even worse during the treatment due to poor positioning of the lenses. In severe cases, it can even lead to corneal distortion.
• Since the daily wear orthokeratology lens can only be worn during daytime, it is not as comfortable as the overnight wear lens.
• Vision correction is not achieved consistently unlike conventional rigid lenses which are used solely to correct vision.
• It is more expensive as it requires the use of more number of lenses. The numbers can reach eight pairs of lenses or more.
• Longer treatment procedure which can take from anywhere between nine to 12 months.
• There is no accurate way of predicting the visual result.
Overnight Wear
Advances in technology allowed the creation of new high-permeability GP materials which now allow overnight wear of orthokeratology shaping lenses instead of wearing them during daytime. This is the preferred method by people suffering from vision problems.
Here are some of its features:
• Because they are easy and convenient to use, patients can adapt faster and easier to this type of lens.
• The new and innovative four, five and six curve reverse geometry designs in large diameters allow users better control of the position of the ortho-k shaping lens.
• There is a more scientific and more accurate means to control and predict the reduction of myopia.
• It can reduce myopia faster as opposed to daily wear lenses. In the past, you need nine to 12 months to get the results that you can now get within 30 days.
• Overnight wear orthokeratology shaping lens come out cheaper than the daily wear version. 70% to 80% of patients who were treated with the overnight wear lens only needed one pair of shaping lenses to achieve their desired reduction of myopia.
Overnight orthokeratology seems to be the way to go for most people. Call us at The Eye Practice on (02) 9290 1899 or BOOK an APPOINTMENT ONLINE for an orthokeratology assessment.
